Ashamed to say, since the FB1.5 out, has not been in the deep excavation of its new features, but when it is an IB to treat a continuation-as long as the smooth transplant, even if OK.
Ashamed to say, since the FB1.5 out, has not been in the deep excavation of its new features, but when it is an IB to treat a continuation-as long as the smooth transplant, even if OK.
It was found in the first two days that the case expression was supported in Firebird 1.5.2. In my opinion, this is a fairly important feature in relational databases, because using case, you can generate a powerful PivotTable report-something that seems to have a special name in spreadsheets like Excel, forgetting what it is. But it's definitely a very useful feature. Of course, we can use spreadsheet software to achieve this function, but it will bring additional network communication burden, and its computational efficiency is much worse.
Here is an example of a perspective that is written using FB's demo database employee:
Select Cust_no
, sum (case when order_status = ' shipped ' then 1 else 0) as shipped
, sum (case when order_status = ' open ' then 1 else 0) as Open
, sum (case when order_status = ' waiting ' then 1 else 0) as waiting
From sales
GROUP BY Cust_no
It generates a result set that is sorted by the processing status of each customer's order.
Because using case, you can generate a powerful PivotTable report-something that seems to have a special name in a spreadsheet like Excel and forget what it is. But it's definitely a very useful feature. Of course, we can use spreadsheet software to achieve this function, but it will bring additional network communication burden, and its computational efficiency is much worse.
Here is an example of a perspective that is written using FB's demo database employee:
Select Cust_no
, sum (case when order_status = ' shipped ' then 1 else 0) as shipped
, sum (case when order_status = ' open ' then 1 else 0) as Open
, sum (case when order_status = ' waiting ' then 1 else 0) as waiting
From sales
GROUP BY Cust_no
It generates a result set that is sorted by the processing status of each customer's order.
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